Vehicle system for determining recommended lane

ABSTRACT

A vehicle system includes: a controller configured to communicate with a map server; and a vehicle position acquiring device configured to acquire own vehicle position information. The controller includes: a vehicle position determining unit configured to determine a lane in which an own vehicle is traveling based on the own vehicle position information; a storage unit configured to store an attendant circumstance of the own vehicle; and a recommended lane determining unit configured to determine a recommended lane. The recommended lane determining unit is configured to set a priority of each lane based on map information, determine the lane having a highest priority as the recommended lane, and exclude a travel prohibited lane, in which travel of the own vehicle is prohibited, from a candidate for the recommended lane based on restriction information and the attendant circumstance.

TECHNICAL FIELD

The present invention relates to a vehicle system for determining arecommended lane for an own vehicle in a case where the own vehicletravels on a road having a plurality of lanes on one lateral sidethereof.

BACKGROUND ART

Map information has been used for vehicle navigation and autonomousdriving (for example, JP2020-20638A). In conventional map information,restriction information and traffic congestion information for eachtravel direction have been included, but information for each lane hasnot been included. In recent years, a high-precision map including therestriction information and the traffic congestion information for eachlane has been proposed (for example, JP2019-184499A).

SUMMARY OF THE INVENTION

If a recommended lane determining device for determining a recommendedlane for an own vehicle can acquire the traffic congestion informationand the restriction information for each lane, then such a device candetermine the recommended lane more appropriately than the conventionaltechnique. In view of such a background, an object of the presentinvention is to provide a vehicle system for determining a recommendedlane for an own vehicle by utilizing a high-precision map so as toimprove driving comfort.

To achieve such an object, one aspect of the present invention providesa vehicle system (2) for determining a recommended lane (41) for an ownvehicle in a case where the own vehicle travels on a road having aplurality of lanes on one lateral side thereof, the vehicle system (2)comprising: a controller (16) configured to communicate with a mapserver (3) that stores map information including traffic information andrestriction information on each lane, the traffic information includingcurrent traffic state information on each lane and/or a statistic of apast traffic state of each lane, the restriction informationcorresponding to an attendant circumstance of the own vehicle selectedfrom a group consisting of (or an attendant circumstance of the ownvehicle including at least one of) the number of occupants, a registerednumber of the own vehicle, a using schedule of a specific lane, and avehicle type; and a vehicle position acquiring device (7, 10) configuredto acquire own vehicle position information for determining the lane inwhich the own vehicle is traveling and transmit the own vehicle positioninformation to the controller (16), wherein the controller (16)includes: a vehicle position determining unit (31) configured todetermine the lane in which the own vehicle is traveling based on theown vehicle position information; a storage unit (34) configured tostore the attendant circumstance of the own vehicle; and a recommendedlane determining unit (32) configured to determine the recommended lane(41), and the recommended lane determining unit (32) is configured toset a priority of each lane based on the map information, determine thelane having a highest priority as the recommended lane (41), and excludea travel prohibited lane from a candidate for the recommended lane (41)based on the restriction information and the attendant circumstance, thetravel prohibited lane being the lane in which travel of the own vehicleis prohibited.

According to this aspect, the lane in which the travel of the ownvehicle is prohibited is excluded from the recommended lane, so that theown vehicle can be prevented from entering such a lane, the comfort ofthe driver can be improved, and the driver can be relieved.

In the above aspect, preferably, the traffic state information includesan average vehicle speed of a plurality of vehicles traveling in eachlane, and the recommended lane determining unit (32) is configured toraise the priority of the lane in which the vehicles are traveling atthe average vehicle speed closest to a target vehicle speed of the ownvehicle.

According to this aspect, the own vehicle can travel at a speed close tothe target vehicle speed, so that the required time to the destinationcan be shortened.

In the above aspect, preferably, the recommended lane determining unit(32) is configured to calculate a congestion degree of each lane basedon the traffic state information and/or the statistic, and lower thepriority of the lane whose congestion degree in front of the own vehicleis equal to or more than a prescribed value.

According to this aspect, the recommended lane is likely to be set so asto avoid a traffic congestion area, so that the required time to thedestination can be shortened.

In the above aspect, preferably, the vehicle system (2) furthercomprises a camera (25) configured to capture a driver, wherein thecontroller (16) further includes an attention determining unit (33)configured to determine an attention level of the driver as to drivingbased on an image captured by the camera (25), and the recommended lanedetermining unit (32) is configured to raise the priority of the lane inwhich the own vehicle is traveling in a case where the attention levelis equal to or less than a prescribed value during manual driving.

According to this aspect, in a case where the attention of the driverdeclines during the manual driving, the lane in which the own vehicle istraveling is likely to be set to the recommended lane, so that the lanechange can be suppressed.

In the above aspect, preferably, the storage unit (34) is configured tostore travel performance information selected from a group consisting of(or travel performance information including at least one of) a traveldistance, a travel time, and a travel frequency of each lane in whichthe own vehicle has traveled during manual driving, and the recommendedlane determining unit (32) is configured to raise the priority of thelane with highest travel performance based on the travel performanceinformation.

According to this aspect, the lane the driver prefers is likely to beset to the recommended lane, so that the comfort of the driver can beimproved.

In the above aspect, preferably, the storage unit (34) is configured tofurther store a preference mode selected from a group consisting of (ora preference mode including): a first preference mode; and a secondpreference mode to suppress a lane change as compared with the firstpreference mode, and the recommended lane determining unit (32) isconfigured to raise the priority of the lane in which the own vehicle istraveling at a time when the preference mode is set to the secondpreference mode as compared with a time when the preference mode is setto the first preference mode.

According to this aspect, the probability of switching of therecommended lane is changed according to the preference of the driver,so that the comfort of the driver can be improved.

Thus, according to the above aspects, it is possible to provide avehicle system for determining a recommended lane for an own vehicle byutilizing a high-precision map so as to improve driving comfort.

BRIEF DESCRIPTION OF THE DRAWING(S)

FIG. 1 is a block diagram showing a map information system according toan embodiment;

FIG. 2 is a flowchart showing how to determine a recommended lane in avehicle system according to the embodiment;

FIG. 3A is an explanatory diagram showing the recommended lane set bythe vehicle system wherein a congestion degree of a branching connectionlane is less than a prescribed value;

FIG. 3B is an explanatory diagram showing the recommended lane set bythe vehicle system wherein the congestion degree of the branchingconnection lane is equal to or more than a prescribed value; and

FIG. 3C is an explanatory diagram showing the recommended lane set bythe vehicle system wherein the branching connection lane is curved infront of the vehicle and before the branching route; and

FIG. 4 is an explanatory diagram showing the recommended lane set by thevehicle system (in a case where a merging route is present) according tothe embodiment.

DETAILED DESCRIPTION OF THE INVENTION

In the following, a map information system 1 according to an embodimentof the present invention will be described with reference to thedrawings.

As shown in FIG. 1, the map information system 1 includes a vehiclesystem 2 mounted on a vehicle, and a map server 3 connected to thevehicle system 2 via a network.

<The Vehicle System>

First, the vehicle system 2 will be described. The vehicle system 2includes a powertrain 4, a brake device 5, a steering device 6, anexternal environment sensor 7, a vehicle sensor 8, a communicationdevice 9, a GNSS receiver 10, a navigation device 11, a drivingoperation member 12, a driving operation sensor 13, an HMI 14, a startswitch 15, and a controller 16. Each component of the vehicle system 2is connected to each other via a communication means such as ControllerArea Network (CAN) such that signals can be transmitted therebetween.

The powertrain 4 is a device configured to apply a driving force to thevehicle. For example, the powertrain 4 includes at least one of aninternal combustion engine (such as a gasoline engine and a dieselengine) and an electric motor. The brake device 5 is a device configuredto apply a brake force to the vehicle. For example, the brake device 5includes a brake caliper configured to press a pad against a brake rotorand an electric cylinder configured to supply an oil pressure to thebrake caliper. The brake device 5 may further include a parking brakedevice configured to restrict rotation of wheels via wire cables. Thesteering device 6 is a device configured to change the steering anglesof the wheels. For example, the steering device 6 includes arack-and-pinion mechanism configured to steer the wheels and an electricmotor configured to drive the rack-and-pinion mechanism. The powertrain4, the brake device 5, and the steering device 6 are controlled by thecontroller 16.

The external environment sensor 7 is a sensor configured to detect anobject outside the vehicle or the like by capturing electromagneticwaves, sound waves, or the like from the surroundings of the vehicle.The external environment sensor 7 includes a plurality of sonars 17 anda plurality of external cameras 18. The external environment sensor 7may further include a millimeter wave radar and/or a laser lidar. Theexternal environment sensor 7 is configured to output a detection resultto the controller 16.

Each sonar 17 consists of a so-called ultrasonic sensor. The sonar 17emits ultrasonic waves to the surroundings of the vehicle and capturesthe reflected waves therefrom, thereby detecting a position (distanceand direction) of the object. The plurality of sonars 17 are provided ata rear part and a front part of the vehicle, respectively.

Each external camera 18 is a device configured to capture an image ofthe surroundings of the vehicle. For example, the external camera 18 isa digital camera that uses a solid imaging element such as a CCD and aCMOS. The external camera 18 may consist of a stereo camera or amonocular camera. The plurality of external cameras 18 include a frontcamera configured to capture an image in front of the vehicle, a rearcamera configured to capture an image behind the vehicle, and a pair ofside cameras configured to capture images on both lateral sides of thevehicle.

The vehicle sensor 8 is a sensor configured to detect the state of thevehicle. The vehicle sensor 8 includes a vehicle speed sensor configuredto detect the speed of the vehicle, an acceleration sensor configured todetect the acceleration of the vehicle, a yaw rate sensor configured todetect the angular velocity around a vertical axis of the vehicle, adirection sensor configured to detect the direction of the vehicle, andthe like. For example, the yaw rate sensor consists of a gyro sensor.The vehicle sensor 8 may further include an inclination sensorconfigured to detect the inclination of a vehicle body and a wheel speedsensor configured to detect the rotational speed of each wheel.

The communication device 9 is configured to mediate communicationbetween the controller 16 and a device (for example, the map server 3)outside the vehicle. The communication device 9 includes a routerconfigured to connect the controller 16 to the Internet. Thecommunication device 9 may have a wireless communication function ofmediating wireless communication between the controller 16 and thecontroller of the surrounding vehicle and between the controller 16 anda roadside device on a road.

The GNSS receiver 10 (the own vehicle position identifying device) isconfigured to receive a signal (hereinafter referred to as “the GNSSsignal”) from each of satellites that constitute a Global NavigationSatellite System (GNSS). The GNSS receiver 10 is configured to outputthe received GNSS signal to the navigation device 11 and the controller16.

The navigation device 11 consists of a computer provided with knownhardware. The navigation device 11 is configured to identify the currentposition (latitude and longitude) of the vehicle based on the previoustravel history of the vehicle and the GNSS signal outputted from theGNSS receiver 10. The navigation device 11 is configured to store data(hereinafter referred to as “the navigation map data”) on roads of aregion or a country on which the vehicle is traveling. The navigationdevice 11 is configured to store the navigation map data in a RAM, anHDD, an SSD, or the like.

The navigation device 11 is configured to set, based on the GNSS signaland the navigation map data, a route from a current position of thevehicle to a destination input by an occupant, and output the route tothe controller 16. When the vehicle starts traveling, the navigationdevice 11 provides the occupant with route guidance to the destination.

The navigation device 11 is configured to store, as information on roadson a map, information on points (nodes) arranged on each road and linesegments (links) connecting the nodes. For example, each node stored inthe navigation device 11 may be provided at a characteristic point suchas an intersection or a merging point. The navigation device 11 isconfigured to store each link in association with a distance between thenodes connected by the link. The navigation device 11 is configured toacquire an appropriate route from the current position of the vehicle tothe destination based on the distances between the nodes, and outputinformation indicating the route to the controller 16. The outputtedinformation indicating the route includes the points (nodes) on the roadcorresponding to the route and the links corresponding to vectorsconnecting the nodes.

The driving operation member 12 is provided in a vehicle cabin andconfigured to accept an input operation the occupant performs to controlthe vehicle. The driving operation member 12 includes a steering wheel,an accelerator pedal, and a brake pedal. The driving operation member 12may further include a shift lever, a parking brake lever, a blinkerlever, and the like.

The driving operation sensor 13 is a sensor configured to detect anoperation amount of the driving operation member 12. The drivingoperation sensor 13 includes a steering angle sensor configured todetect an operation amount of the steering wheel, an accelerator sensorconfigured to detect an operation amount of the accelerator pedal, and abrake sensor configured to detect an operation amount of the brakepedal. The driving operation sensor 13 is configured to output thedetected operation amount to the controller 16. The driving operationsensor 13 may further include a grip sensor configured to detect thatthe occupant grips the steering wheel. For example, the grip sensorconsists of at least one capacitive sensor provided on an outercircumferential portion of the steering wheel.

The HMI 14 is configured to notify the occupant of various kinds ofinformation by display and/or voice, and accept an input operation bythe occupant. For example, the HMI 14 includes a touch panel 23 and asound generating device 24. The touch panel 23 includes a liquid crystaldisplay, an organic EL display, or the like, and is configured to acceptthe input operation by the occupant. The sound generating device 24consists of a buzzer and/or a speaker. The HMI 14 is configured todisplay a driving mode switch button on the touch panel 23. The drivingmode switch button is a button configured to accept a switchingoperation of a driving mode (for example, an autonomous driving mode anda manual driving mode) of the vehicle by the occupant.

The HMI 14 also functions as an interface to mediate the input to/theoutput from the navigation device 11. Namely, when the HMI 14 acceptsthe input operation of the destination by the occupant, the navigationdevice 11 starts a route setting to the destination. Further, when thenavigation device 11 provides the route guidance to the destination, theHMI 14 displays the current position of the vehicle and the route to thedestination.

The start switch 15 is a switch for starting the vehicle system 2.Namely, the occupant presses the start switch 15 while sitting on thedriver's seat and pressing the brake pedal, and thus the vehicle system2 is started.

The controller 16 consists of at least one electronic control unit (ECU)including a CPU, a ROM, a RAM, and the like. The CPU executes operationprocessing according to a program, and thus the controller 16 executesvarious types of vehicle control. The controller 16 may consist of onepiece of hardware, or may consist of a unit including plural pieces ofhardware. The functions of the controller 16 may be at least partiallyexecuted by hardware such as an LSI, an ASIC, and an FPGA, or may beexecuted by a combination of software and hardware.

The vehicle system 2 further includes an in-cabin camera 25 forcapturing the occupant (for example, the driver) of the vehicle. Forexample, the in-cabin camera 25 consists of a digital camera using asolid imaging element such as a CCD or a CMOS. The in-cabin camera 25 isconfigured to output a capturing result to the controller 16. Thecontroller 16 is configured to identify the driver based on thecapturing result of the in-cabin camera 25, and store the driver and thedata relating to the driving performance (travel performance) thereofsuch that the driver and the date are associated with each other.

<The Controller 16>

As shown in FIG. 1, the controller 16 includes an autonomous drivingcontrol unit 30 (Advanced Driver-Assistance Systems: ADAS), a vehicleposition determining unit 31, a recommended lane determining unit 32, anattention determining unit 33, a storage unit 34, and a probeinformation acquiring unit 35. These components may be composed ofseparate electronic control units and connected to each other via agateway (central gateway: CGW). Alternatively, these components may becomposed of an integrated electronic control unit.

The vehicle position determining unit 31 is configured to determine thecurrent position of the vehicle based on own vehicle positioninformation from a vehicle position acquiring device, namely, based onthe detection result of the external environment sensor 7 and the GNSSsignal from the GNSS receiver 10. The object recognized based on thedetection result of the external environment sensor 7 includesdelimiting lines, lanes, road ends, road shoulders, obstacles, and thelike, which are present on a travel route of the vehicle. In a casewhere the vehicle is traveling on a road having a plurality of lanes,the vehicle position determining unit 31 determines the lane in whichthe vehicle (the own vehicle) is traveling.

Each delimiting line is a line shown along a vehicle travel direction.Each lane is an area delimited by one or more delimiting lines. Eachroad end is an end of the travel route of the vehicle. Each roadshoulder is an area between the delimiting line arranged at an end inthe vehicle width direction and the road end. For example, each obstaclemay be a barrier (guardrail), a utility pole, a surrounding vehicle, apedestrian, or the like.

The vehicle position determining unit 31 is configured to recognize theposition of the object around the vehicle with respect to the vehicle byanalyzing the image captured by each external camera 18. For example,the vehicle position determining unit 31 may recognize the distance anddirection from the vehicle to the object in a top view around thevehicle body by using a known method such as a triangulation method or amotion stereo method. Further, the vehicle position determining unit 31is configured to analyze the image captured by the external camera 18,and determine the type (for example, the delimiting line, the lane, theroad end, the road shoulder, the obstacle, or the like) of each objectbased on a known method.

The vehicle position determining unit 31 is configured to calculate amovement amount (a movement distance and a movement direction:hereinafter referred to as “the DR movement amount”) of the vehicle byusing dead reckoning (for example, odometry) based on a detection resultof the vehicle sensor 8 such as Inertial Measurement Unit (IMU). Forexample, the vehicle position determining unit 31 is configured toidentify an own vehicle position based on the DR movement amount whenthe GNSS signal cannot be received. Further, the vehicle positiondetermining unit 31 may execute a process for improving theidentification accuracy of the own vehicle position by correcting, basedon the DR movement amount, the own vehicle position identified from theGNSS signal.

The recommended lane determining unit 32 is configured to determine atleast one recommended lane 41 for the own vehicle based on the routeoutputted from the navigation device 11 and the information receivedfrom the map server 3. For example, in a case where the route receivedfrom the navigation device 11 includes a branching route 45, therecommended lane determining unit 32 adds data, which indicates asuitable lane for the travel of the vehicle, to recommended laneinformation on a lane link (for example, a lane link of the lane closestto the branching route 45 in a position 2 km before an entrance to thebranching route 45) corresponding to a lane suitable for entering thebranching route 45, thereby causing the storage unit 34 to store therecommended lane information.

The attention determining unit 33 is configured to determine anattention level of the driver as to driving based on the capturingresult of the in-cabin camera 25. For example, in a case where thedriver's sightline is directed to a place other than the front of thevehicle for a prescribed time period or more, or in a case where thedriver takes his/her hands off the steering wheel, the attentiondetermining unit 33 determines that the attention level of the driver asto driving declines.

The storage unit 34 includes a storage device such as an HDD and an SSD,and is configured to store the information received by the controller16. The storage unit 34 is configured to store an attendant circumstanceof the vehicle, a preference mode, a driving mode, and travelperformance information (driving performance information). The attendantcircumstance of the vehicle is selected from a group consisting of (orthe attendant circumstance of the vehicle includes at least one of) thenumber of occupants, a registered number of the own vehicle, a usingschedule of a specific lane, and a vehicle type. The travel performanceinformation is selected from a group consisting of (or the travelperformance information includes at least one of) a travel distance, atravel time, and a travel frequency of each lane in which the ownvehicle has traveled during manual driving. Preferably, the controller16 identifies the drivers based on the capturing result of the in-cabincamera 25, and the travel performance information is recorded for eachdriver. The specific lane includes a customs-only lane for vehicles withan occupant that requires payment in the customs and an ETC lane forvehicles compatible with an Electronic Toll Collection System (ETC). TheETC lane is provided near a tollgate of a toll road. The vehicle typeincludes a type that is classified according to the size and/or weightof the vehicle (for example, a large vehicle or a compact vehicle) and atype classified according to the use (purpose) of the vehicle (forexample, an emergency vehicle such as an ambulance or a shared bus). Thepreference mode is selected from a group consisting of (or thepreference mode includes) a sports mode (first preference mode) in whichthe vehicle travels by utilizing its kinetic performance and an ecologymode (a second preference mode) to reduce a load on the environment. Thepreference mode indicates a driving method the driver prefers, and isset by the occupant (for example, the driver) by using an input devicesuch as the touch panel 23.

The driving mode is selected from the manual driving mode and theautonomous driving mode, and set by the occupant (driver) by using aninput device such as the touch panel 23. In the manual driving mode, thecontroller 16 controls the powertrain 4, the brake device 5, and thesteering device 6 in response to the input operation on the drivingoperation member 12 (for example, the steering wheel, the acceleratorpedal and/or the brake pedal) by the occupant, thereby causing thevehicle to travel. On the other hand, in the autonomous driving mode,the occupant does not need to perform the input operation on the drivingoperation member 12, and the autonomous driving control unit 30 controlsthe powertrain 4, the brake device 5, and the steering device 6, therebycausing the vehicle to travel autonomously. Namely, a driving automationlevel of the autonomous driving mode is higher than that of the manualdriving mode.

The controller 16 is configured to access the map server 3 and acquiredynamic map data, which is high-precision map information, from the mapserver 3. For example, as the navigation device 11 sets the route, thecontroller 16 acquires the latest dynamic map data of an areacorresponding to the route from the map server 3 via the communicationdevice 9.

The dynamic map data is more detailed than the navigation map datastored in the navigation device 11, and includes static information,semi-static information, semi-dynamic information, and dynamicinformation. The static information includes 3D map data that is moreprecise than the navigation map data stored in the navigation device 11.The semi-static information includes traffic regulation information,road construction information, and wide area weather information. Thesemi-dynamic information includes accident information, trafficcongestion information, and small area weather information. The dynamicinformation includes signal information, surrounding vehicleinformation, and pedestrian information.

The static information (the high-precision map) of the dynamic map dataincludes information on the lanes (for example, the number of lanes) onthe travel route and information on each delimiting line (for example,the type of the delimiting line) on the travel route. For example, thedelimiting line of the static information is expressed as nodes arrangedat smaller intervals than the nodes of the navigation map data and linksconnecting the nodes. The traffic regulation information, the roadconstruction information, the accident information, and the trafficcongestion information are stored for each lane.

The controller 16 is configured to acquire the high-precision map in arelatively narrow area around the vehicle and in front of the vehicle inthe vehicle travel direction based on the own vehicle positionidentified by the vehicle position determining unit 31 and the route setby the navigation device 11. The vehicle position determining unit 31 isconfigured to identify the acquired high-precision map, the travel lane,and the own vehicle position in the travel lane based on the position ofthe delimiting line detected by the external environment sensor 7 or thelike.

The probe information acquiring unit 35 associates the own vehicleposition identified based on the GNSS signal with the data detected byat least one of the vehicle sensor 8 (vehicle state sensor), the drivingoperation sensor 13, and the external environment sensor 7, therebyacquiring and storing the own vehicle position and the data as probeinformation.

<The Map Server>

Next, the map server 3 will be described. As shown in FIG. 1, the mapserver 3 is connected to the controller 16 via the network (in thepresent embodiment, the Internet). The map server 3 is a computerincluding a CPU, a ROM, a RAM, and a storage unit such as an HDD and anSSD.

The dynamic map data is stored in the storage unit of the map server 3.The dynamic map data stored in the storage unit of the map server 3covers a wider area than the dynamic map data stored in the controller16.

Upon receiving a request for data from the controller 16 via thecommunication device 9, the map server 3 transmits the dynamic map datacorresponding to the requested data to the corresponding controller 16.The transmitted dynamic map data may include the traffic congestioninformation, the weather information, and the like.

The vehicle system 2 is started as the occupant boards the vehicle andpushes the start switch 15 while pressing the brake pedal. In theautonomous driving mode, as the occupant inputs the destination andperforms the input operation on the HMI 14 for starting autonomousdriving, the vehicle travels autonomously to reach the destination. Inthe manual driving mode, as the occupant inputs the destination, thenavigation device 11 provides the route guidance to the destination.

<Determination of the Recommended Lane>

Next, the determination of the recommended lane 41 will be describedwith reference to FIGS. 1 to 4. In FIGS. 3A to 3C and 4, the vehicletravel direction (which is shown by an arrow Z) is a direction from aleft side to a right side therein. On a road having a plurality of laneson one lateral side (namely, on a road having a plurality of lanes inthe same vehicle travel direction), the recommended lane determiningunit 32 determines the recommended lane 41 shown in FIGS. 3A to 3C and 4along a flow shown in FIG. 2 in both the autonomous driving mode and themanual driving mode. In the autonomous driving mode, the controller 16controls the own vehicle such that the own vehicle travels in therecommended lane 41. In the manual driving mode, the navigation device11 causes the touch panel 23 to display the recommended lane 41, andcauses the sound generating device 24 to guide the driver by voice tomove the vehicle to the recommended lane 41. In a case where therecommended lane 41 is switched from one lane to another according tothe travel of the vehicle in the autonomous driving mode, the controller16 starts a lane change process (which includes a series of processes ofconfirming safety based on the detection result of the externalenvironment sensor 7, blinking a turn signal, moving the vehicle to therecommended lane 41, and turning off the turn signal) at a switchingpoint 42. In a case where the recommended lane 41 is switched asdescribed above in the manual driving mode, the navigation device 11causes the touch panel 23 and the sound generating device 24, at orbefore the switching point 42, to notify the driver that the recommendedlane 41 is switched.

Depending on attendant circumstances of vehicles, the travel of vehicleswith a specific attendant circumstance is prohibited in some lanes,while only the travel of vehicles with a specific attendant circumstanceis permitted in other lanes. The criteria for suchprohibition/permission are different depending on a country or region.For example, in some lanes such as High-Occupancy Vehicles lanes (HOVlanes) in the United States, only the travel of vehicles whose number ofoccupants is equal to or more than a prescribed number may be permitted.Further, in some countries such as China, the lanes in which vehiclescan travel may change depending on the registered number of eachvehicle. Further, lanes for vehicles with an occupant who performs aprescribed procedure at the customs may be provided, or lanes forvehicles compatible with ETC may be provided at a tollgate of a tollroad. Further, lanes in which vehicles can travel may be set accordingto the vehicle type (for example, lanes for buses only or lanes in whichthe travel of large vehicles is prohibited may be provided).

The map information (dynamic map data) stored in the map server 3includes restriction information for each lane according to such anattendant circumstance of each vehicle. The storage unit 34 storesinformation on the attendant circumstance, which is the informationnecessary in the country or region where the vehicle travels. Theattendant circumstance of the vehicle is selected from a groupconsisting of the number of occupants, the registered number of the ownvehicle, the using schedule of the specific lane, and the vehicle type.The occupant or the like may input the attendant circumstance on thetouch panel 23. The controller 16 may calculate the number of occupantsbased on the capturing result of the in-cabin camera 25. Alternatively,in a case where the vehicle sensor 8 includes a sensor such as apiezoelectric element installed in each seat, the controller 16 maycalculate the number of occupants based on the detection result of sucha sensor. The recommended lane determining unit 32 excludes a travelprohibited lane 43, in which the travel of the own vehicle isprohibited, from a candidate for the recommended lane 41 based on theattendant circumstance of the own vehicle stored in the storage unit 34and the information received from the map server 3 (S1 in FIG. 2).Namely, the recommended lane determining unit 32 determines a travelpermitted lane in which the travel of the vehicle is permitted.

The recommended lane determining unit 32 sets a priority of each lanebased on traffic state information (map information) for each lanereceived from the map server 3 (S2 in FIG. 2), and determines therecommended lane 41 according to the priority (S3 in FIG. 2). Forexample, the recommended lane determining unit 32 may convert thepriority into a numerical value so as to determine that the prioritygets higher as the numerical value gets larger. The recommended lanedetermining unit 32 may increase or decrease the priority by increasingor decreasing the numerical value according to the event that causessuch an increase or decrease of the priority, by multiplying thenumerical value by a coefficient corresponding to the event, or by thecombination of these methods. The recommended lane determining unit 32may exclude the travel prohibited lane 43 from the candidate for therecommended lane 41 by minimizing the priority of the travel prohibitedlane 43.

The recommended lane determining unit 32 may lower the priority of thelane that is congested or likely to be congested in front of the vehiclein the vehicle travel direction depending on a congestion degree and thedistance to a congested point. The controller 16 determines thecongestion degree based on a current average vehicle speed in each lanereceived from the map server 3 and the statistic such as a past averagevehicle speed in each lane classified according to a day of a week and atime of the day. Further, the recommended lane determining unit 32 maylower the priority of the lane having an impassable point (a point wherethe vehicle cannot pass through due to construction, an accident, or thelike) in front of the vehicle in the vehicle travel direction accordingto the distance to the impassable point.

The recommended lane determining unit 32 may raise the priority of abranching connection lane 44 connected to the branching route 45 thatleads to the destination as the own vehicle approaches the branchingroute 45. The recommended lane determining unit 32 may raise thepriority of the lane in which vehicles are traveling at an averagevehicle speed closest to a target vehicle speed of the own vehiclestored in the storage unit 34, or raise the priority of the lane whosespeed limit is closest to the target vehicle speed of the own vehicleamong the lanes whose speed limit is equal to or higher than the targetvehicle speed of the own vehicle stored in the storage unit 34. Theoccupant may set the target vehicle speed of the own vehicle by using aninput device such as the touch panel 23. Alternatively, the controller16 may calculate the target vehicle speed of the own vehicle based onthe driving performance data of the driver at the same or similarlocation stored in the storage unit 34 and/or the speed limit of theroad or the lane received from the map server 3.

During the manual driving, in a case where the attention level of thedriver as to driving determined by the attention determining unit 33becomes equal to or less than a prescribed value, the recommended lanedetermining unit 32 may raise the priority of the lane in which the ownvehicle is traveling so as to suppress a lane change. In a case wherethe attention level of the driver as to driving determined by theattention determining unit 33 is higher than the prescribed value, therecommended lane determining unit 32 may enlarge the raising/loweringrange of the priority due to the other factors since switching of therecommended lane 41 is allowed.

The recommended lane determining unit 32 may raise the priority of thelane (for example, a left end lane, a middle lane, or the like) thedriver prefers. The driver may set the lane the driver prefers by usingan input device such as the touch panel 23, and thus the storage unit 34may store the lane the driver prefers set by the driver. Alternatively,the controller 16 may determine the lane the driver prefers based on thedriving performance information (travel performance information) storedin the storage unit 34, more specifically, based on the drivingperformance information at a time when the vehicle has traveled in alocation with the same or similar road structure. The drivingperformance information is selected from a group consisting of (or thedriving performance information includes at least one of) a traveldistance, a travel time, and a travel frequency of each lane. Therecommended lane determining unit 32 may determine the lane with thehighest travel performance as the lane the driver prefers.

In the ecology mode, acceleration/deceleration of the vehicle issuppressed as compared with the sports mode so as to reduce the load onthe environment. In a case where the vehicle performs the lane change,the acceleration/deceleration of the vehicle may be required so as toadapt to the flow of other vehicles in the lane the vehicle will enter.Namely, the ecology mode is a mode in which the lane change should besuppressed as compared with the sports mode. Accordingly, therecommended lane determining unit 32 raises the priority of the lane inwhich the own vehicle is traveling in a case where the preference modeis set to the ecology mode as compared with a case where the preferencemode is set to the sports mode.

Upon determining based on the priority that the recommended lane 41should be switched to another lane, the recommended lane determiningunit 32 adjusts the switching point 42 (S4 in FIG. 2). The recommendedlane determining unit 32 adjusts the switching point 42 based on thecongestion degree of a lane (a branching connection lane 44 in FIGS. 3Ato 3C and a merging connection lane 47 in FIG. 4) to be switched to therecommended lane 41, the road structure, the vehicle type, thepreference of the driver, or the combination of these factors.

FIGS. 3A to 3C each show a situation in which the recommended lane 41 isswitched from the middle lane of the three lanes to the branchingconnection lane 44 on the left side so that the vehicle can enter thebranching route 45. FIG. 3A shows a case where the branching connectionlane 44 is not congested or not expected to be congested in front of thevehicle and before the branching route 45. Namely, FIG. 3A shows a casewhere the congestion degree of the branching connection lane 44 is lessthan a prescribed value. FIG. 3B shows a case where the branchingconnection lane 44 is congested or expected to be congested in front ofthe vehicle and before the branching route 45. Namely, FIG. 3B shows acase where the congestion degree of the branching connection lane 44 isequal to or more than a prescribed value. The recommended lanedetermining unit 32 may shift the switching point 42 of the recommendedlane 41 more rearward in the vehicle travel direction in a case wherethe congestion degree of the lane to be switched to the recommended lane41 is equal to or more than the prescribed value, as compared with acase where the congestion degree thereof is less than the prescribedvalue.

FIG. 3C shows a case where the branching connection lane 44 is curved infront of the vehicle and before the branching route 45, which causespoor visibility. In a case where the road structure of the lane to beswitched to the recommended lane 41 is curved, the recommended lanedetermining unit 32 may shift the switching point 42 of the recommendedlane 41 more rearward in the vehicle travel direction as compared with acase where the road structure thereof is straight.

At an exit of a rest area or a parking area, an interchange, or ajunction, the recommended lane determining unit 32 may switch therecommended lane 41 to the merging connection lane 47 to which a mergingroute 46 is connected in the vicinity of a merging point M of themerging route 46 with the merging connection lane 47. In such a case,the recommended lane determining unit 32 may set the switching point 42more forward in the vehicle travel direction than the merging point M(FIG. 4).

In a case where the own vehicle is a vehicle (for example, an emergencyvehicle) that can travel preferentially over other vehicles, therecommended lane determining unit 32 may shift the switching point 42 ofthe recommended lane 41 more forward in the vehicle travel direction ascompared with a case where the own vehicle is a common vehicle oncondition that the congestion degree or the average vehicle speed of thelane in which the own vehicle is traveling is lower than that of thelane to be switched to the recommended lane 41.

The storage unit 34 may store the preference of the driver for a timingof the lane change to the recommended lane 41, and the recommended lanedetermining unit 32 may adjust the switching point 42 of the recommendedlane 41 according to the preference thereof. Preferably, such anadjustment of the switching point 42 according to the preference of thedriver is executed during the manual driving mode.

The vehicle position determining unit 31 calculates a difference betweenan actual start position of the lane change process during the manualdriving and a position to be set to the switching point 42 during theautonomous driving, and the storage unit 34 stores this difference asthe past driving performance data (travel performance data). During themanual driving, the recommended lane determining unit 32 may shift theswitching point 42 from the position to be set to the switching point 42during the autonomous driving by a distance corresponding to arepresentative value of the difference stored in the storage unit 34.The representative value of the difference is an average value, acentral value, or the most frequent value of the difference. Theoccupant may input the distance by which the switching point 42 isshifted by using an input device such as the touch panel 23, and thestorage unit 34 may store the above distance. Alternatively, therecommended lane determining unit 32 may determine the representativevalue by classifying and totaling up the difference according to theroad structure or the congestion degree.

In the ecology mode, the acceleration/deceleration of the vehicle issuppressed as compared with the sports mode so as to reduce the load onthe environment. In a case where the vehicle performs the lane change,sudden acceleration/deceleration (including acceleration/deceleration inthe lateral direction) of the vehicle may be required so as to adapt tothe flow of the vehicles in the lane the vehicle will enter. Namely, theecology mode is a mode in which the sudden acceleration/decelerationshould be suppressed as compared with the sports mode. Accordingly, therecommended lane determining unit 32 may shift the switching point 42more rearward in the vehicle travel direction at a time when thepreference mode is set to the ecology mode as compared with a time whenthe preference mode is set to the sports mode so that the vehicle hasenough time to execute the lane change. Particularly, it is preferableto execute this process in a case where the recommended lane 41 isswitched to the branching connection lane 44 to cause the vehicle toenter the branching route 45.

According to the above configurations, the lane to which the entry ofthe own vehicle is prohibited (namely, the lane in which the travel ofthe own vehicle is prohibited) is excluded from the candidate for therecommended lane 41, so that the relief and comfort of the driver can beimproved. The lane in which other vehicles are traveling at an averagevehicle speed close to a target vehicle speed of the own vehicle or thelane that is not congested is preferentially determined as therecommended lane 41, so that the required time to the destination isshortened. When the attention of the driver declines during the manualdriving, the recommended lane 41 is unlikely to be switched. The lanethe driver prefers is likely to be set to the recommended lane 41, andthe number of lane changes increases/decreases depending on thepreference mode, so that the comfort of the driver can be improved.

The switching point 42 is adjusted according to the congestion degree ofthe lane to be switched to the recommended lane 41, so that the drivercan be relieved. Further, it is possible to prevent a situation wherethe vehicle cannot perform the lane change to the branching connectionlane 44 as the distances between the vehicles traveling on the branchingconnection lane 44 are too short. Also, it is possible to prevent asituation where the own vehicle disturbs the travel of the followingvehicle as the own vehicle is decelerated just before the branchingroute 45 and aggressively entering the branching connection lane 44.When the recommended lane 41 is switched to the branching connectionlane 44 which has a curve with poor visibility, the switching point 42is shifted rearward, so that the driver's anxiety due to theinvisibility of the branching route 45 can be alleviated. In a casewhere the recommended lane 41 is switched to the merging connection lane47 in the vicinity of the merging point M of the merging route 46 in themerging connection lane 47, the switching point 42 is shifted moreforward than the merging point M, so that it is possible to prevent theown vehicle from disturbing the travel of another vehicle that is goingto merge.

As described above, the recommended lane determining unit 32 determinesthe recommended lane 41 by utilizing the information on each lane storedin the map server 3, and thus the vehicle system 2 according to thepresent embodiment contributes to secure and comfortable travel of thevehicle.

Concrete embodiments of the present invention have been described in theforegoing, but the present invention should not be limited by theforegoing embodiments and various modifications and alterations arepossible within the scope of the present invention.

1. A vehicle system for determining a recommended lane for an ownvehicle in a case where the own vehicle travels on a road having aplurality of lanes on one lateral side thereof, the vehicle systemcomprising: a controller configured to communicate with a map serverthat stores map information including traffic information andrestriction information on each lane, the traffic information includingcurrent traffic state information on each lane and/or a statistic of apast traffic state of each lane, the restriction informationcorresponding to an attendant circumstance of the own vehicle selectedfrom a group consisting of the number of occupants, a registered numberof the own vehicle, a using schedule of a specific lane, and a vehicletype; and a vehicle position acquiring device configured to acquire ownvehicle position information for determining the lane in which the ownvehicle is traveling and transmit the own vehicle position informationto the controller, wherein the controller includes: a vehicle positiondetermining unit configured to determine the lane in which the ownvehicle is traveling based on the own vehicle position information; astorage unit configured to store the attendant circumstance of the ownvehicle; and a recommended lane determining unit configured to determinethe recommended lane, and the recommended lane determining unit isconfigured to set a priority of each lane based on the map information,determine the lane having a highest priority as the recommended lane,and exclude a travel prohibited lane from a candidate for therecommended lane based on the restriction information and the attendantcircumstance, the travel prohibited lane being the lane in which travelof the own vehicle is prohibited.
 2. The vehicle system according toclaim 1, wherein the traffic state information includes an averagevehicle speed of a plurality of vehicles traveling in each lane, and therecommended lane determining unit is configured to raise the priority ofthe lane in which the vehicles are traveling at the average vehiclespeed closest to a target vehicle speed of the own vehicle.
 3. Thevehicle system according to claim 1, wherein the recommended lanedetermining unit is configured to calculate a congestion degree of eachlane based on the traffic state information and/or the statistic, andlower the priority of the lane whose congestion degree in front of theown vehicle is equal to or more than a prescribed value.
 4. The vehiclesystem according to claim 1, further comprising a camera configured tocapture a driver, wherein the controller further includes an attentiondetermining unit configured to determine an attention level of thedriver as to driving based on an image captured by the camera, and therecommended lane determining unit is configured to raise the priority ofthe lane in which the own vehicle is traveling in a case where theattention level is equal to or less than a prescribed value duringmanual driving.
 5. The vehicle system according to claim 1, wherein thestorage unit is configured to store travel performance informationselected from a group consisting of a travel distance, a travel time,and a travel frequency of each lane in which the own vehicle hastraveled during manual driving, and the recommended lane determiningunit is configured to raise the priority of the lane with highest travelperformance based on the travel performance information.
 6. The vehiclesystem according to claim 1, wherein the storage unit is configured tofurther store a preference mode selected from a group consisting of: afirst preference mode; and a second preference mode to suppress a lanechange as compared with the first preference mode, and the recommendedlane determining unit is configured to raise the priority of the lane inwhich the own vehicle is traveling at a time when the preference mode isset to the second preference mode as compared with a time when thepreference mode is set to the first preference mode.
 7. A vehicle systemfor determining a recommended lane for an own vehicle in a case wherethe own vehicle travels on a road having a plurality of lanes on onelateral side thereof, the vehicle system comprising: a controllerconfigured to communicate with a map server that stores map informationincluding traffic information and restriction information on each lane,the traffic information including current traffic state information oneach lane and/or a statistic of a past traffic state of each lane, therestriction information corresponding to an attendant circumstance ofthe own vehicle including at least one of the number of occupants, aregistered number of the own vehicle, a using schedule of a specificlane, and a vehicle type; and a vehicle position acquiring deviceconfigured to acquire own vehicle position information for determiningthe lane in which the own vehicle is traveling and transmit the ownvehicle position information to the controller, wherein the controllerincludes: a vehicle position determining unit configured to determinethe lane in which the own vehicle is traveling based on the own vehicleposition information; a storage unit configured to store the attendantcircumstance of the own vehicle; and a recommended lane determining unitconfigured to determine the recommended lane, and the recommended lanedetermining unit is configured to set a priority of each lane based onthe map information, determine the lane having a highest priority as therecommended lane, and exclude a travel prohibited lane from a candidatefor the recommended lane based on the restriction information and theattendant circumstance, the travel prohibited lane being the lane inwhich travel of the own vehicle is prohibited.
 8. The vehicle systemaccording to claim 7, wherein the storage unit is configured to storetravel performance information including at least one of a traveldistance, a travel time, and a travel frequency of each lane in whichthe own vehicle has traveled during manual driving, and the recommendedlane determining unit is configured to raise the priority of the lanewith highest travel performance based on the travel performanceinformation.
 9. The vehicle system according to claim 7, wherein thestorage unit is configured to further store a preference mode including:a first preference mode; and a second preference mode to suppress a lanechange as compared with the first preference mode, and the recommendedlane determining unit is configured to raise the priority of the lane inwhich the own vehicle is traveling at a time when the preference mode isset to the second preference mode as compared with a time when thepreference mode is set to the first preference mode.